In our aging society where the relative proportion of people 65 years and older in the entire population is on the increase, the number of patients suffering from high blood pressure, atherosclerosis, and other lifestyle-related diseases has been increasing. The number of individuals who have a high risk of developing such diseases has also been increasing. For example, the majority of adults aged 50 or above develops high blood pressure, a risk factor for diabetes, hyperlipidemia, stroke, heart disease, and other lifestyle-related diseases. It has recently been suggested that people of 50 years old or older also have the risk of a condition known as prehypertension.
High blood pressure results from various causes, including an unbalanced diet, insufficient exercise, and other lifestyle-related factors, stress, intake of vasopressor substances and hereditary traits. These causes are often combined. For this reason, sufferers of high blood pressure need to take different drugs depending on the particular cause to maintain their blood pressure within the normal range. However, it is often difficult to identify and prescribe drugs optimal to a given patient. Furthermore, even when optimal drugs can be prescribed, the patient needs to take such drugs over a long course of treatment, in some cases for the rest of his/her life.
Under such circumstances, the importance of diet in the primary prevention of high blood pressure and other lifestyle-related diseases has become widely recognized. This recognition now serves as the driving force behind the emerging market of health food products, nutritional supplements, food products for specified health uses, nutritionally modified food products, and various other health-oriented functional food products.
Of the many health-oriented functional food products intended for the primary prevention of lifestyle-related diseases including high blood pressure, nutritionally modified functional food products in particular have become widely available. Nutritionally modified functional food products are common food products that have functional or nutritional ingredients added to them. Among such food products are a group of health beverages and food products that make use of intermediate sea water collected at a depth of up to about 300 m. These products, however, are put on the market without scientific investigation of their functionality. There are also health beverages and food products that use deep sea water. In these products, the sea water is generally used as merely a source of minerals (Patent Documents Nos. 1, 2, 3, 4, and 5).
It is known well that Na, Ca, Mg, and other elements are present in sea water (Non-Patent Document No. 6). It is also known well that Na (Non-Patent Document No. 7) and Mg (Non-Patent Document No. 8) play significant roles in the regulation of blood pressure.
One study suggests that what makes deep sea water different from surface sea water is that nutrient salts such as nitrogen-containing salts, phosphorus-containing salts, and silicon-containing salts are present at higher concentrations (Non-Patent Document No. 10). However, no studies have been reported which focus on the ability of deep sea water from the standpoint of the suppression of blood pressure elevation.
As far as silicon (Si) is concerned, it has only been mentioned that in human bodies, the element is most abundant in the aorta and decreases as people grow old, and that the decrease is more prominent in sclerosed arteries than in intact arteries (Non-Patent Document No. 11).
[Patent Document No. 1] Japanese Patent Application Laid-Open No. 2000-295974
[Patent Document No. 2] Japanese Patent Application Laid-Open No. 2001-48528
[Patent Document No. 3] Japanese Patent Application Laid-Open No. 2001-79566
[Patent Document No. 4] Japanese Patent Application Laid-Open No. 2001-190255
[Patent Document No. 5] Japanese Patent Application Laid-Open No. 2001-190256
[Non-Patent Document No. 6] Aquabiology 23(4): 343-349, 2001
[Non-Patent Document No. 7] Brit Med J 297: 319-328, 1988
[Non-Patent Document No. 8] Science 223: 1315-1317, 1984
[Non-Patent Document No. 9] Hypertension 13: 227-232, 1989
[Non-Patent Document No. 10] Aquabiology, 23(4): 343-349, 2001
[Non-Patent Document No. 11] Biochemistry of Silicon and Related Problems, G. Bendz and I. Lindquist, eds., Plenum press, New York, 1978, pp. 281-296.